This is for IGCSE Double Award Biology (EDEXCEL), tailored to the 2009 specification. If you spot any mistakes, please let me know, thank you! I hope you find this useful!
This blog is no longer updated as I've finished IGCSEs in 2012. I may sometimes reply to questions if you comment or email me, but not guaranteed. I hope what I had time to post back during IGCSEs helps anyway!! :)

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Thursday, 26 April 2012

Keywords Glossary

Somebody asked for a glossary, well here's all I have. There's so many bio words out there so obviously I can't include everything, so anything not here, just you know, Google it. :P

Keywords

Active
transport: The process in
which energy is used to move the particles of a substance against a
concentration gradient, that is, from a region where they are of lower
concentration to a region where they are of higher concentration.

Adaptation:
Any characteristic of an
organism that improves its chances of surviving in its environment.

Aerobic
respiration: Respiration with
oxygen. It’s the oxidation of food substances in the presence of oxygen with
the release of a large amount of energy. Carbon dioxide and water are released
as waste products.

AIDS:
An abbreviation for Acquired
Immune Deficiency Syndrome.

Alleles:
Different forms of a gene
which occupy the same relative positions on a pair of homologous chromosomes.

Anaerobic
respiration: Respiration
without oxygen. It’s the oxidation of food substances in the absence of oxygen.
Anaerobic respiration releases less energy than aerobic respiration.

Anaesthetics:
Drugs that make the body
unable to feel pain.

Arteries:
Blood vessels which carry
blood away from the heart.

Artificial
selection: A method used by
human beings to produce plants and animals with desired qualities.

Asexual
reproduction: The process
resulting in the production of genetically identical offspring from one parent,
without the fusion of gametes.

Assimilation:
The process whereby some of
the absorbed food materials are converted into new protoplasm or used to
provide energy.

Axon:
A nerve fibre that transmits
impulses away from the cell body of a neurone.

Bioaccumulation:
The process by which
substances collect in all parts or part of a living organism.

Breathing:
The process that brings about
an exchange of gases between an organism and its environment.

Capillaries:
Microscopic thin-walled (one
cell thick) blood vessels which carry blood from a small artery (arteriole) to
a small vein (venule).

Codominance:
A condition where both alleles
express themselves in a hybrid, as they are both either dominant or recessive
to one another. (Roughly equal expression.)

Community:
Populations of organisms
living together and interacting with one another under the same environmental
conditions.

Conservation:
The protection and
preservation of natural resources of the environment.

Consumers:
Organisms which obtain their
energy by feeding on other organisms.

Continuous
variation: Traits with
phenotypes ranging from one extreme to the other. It is brought about by
combined (or additive) effects of many genes. It is affected by environmental
conditions, e.g. intelligence, height and skin colour in human beings.

Cross-pollination:
The transfer of pollen grains
from one plant to the stigma of a flower in another plant of the same species.

Dendron:
A nerve fibre that transmits
impulses towards the cell body of a neurone.

Desertification:
The destruction of land
leading to desert-like conditions.

Detoxification:
The process of converting
harmful substances into harmless ones in the body.

Differentiation:
The process by which a cell
becomes specialized for a specific function.

Diffusion:
The net movement of particles
(atoms, ions or molecules) from a region of higher concentration to a region of
lower concentration, that is, down a concentration gradient.

Digestion:
The process by which large
food molecules are broken down into small, soluble and diffusible molecules
that can be absorbed by the body cells.

Diploid:
Cells that contain the full
number of chromosomes.

Discontinuous
variation: Traits that show
limited variation in their phenotypes which are easily distinguishable. It is usually
controlled by only one or a few genes. It is not affected by the environment.
E.g. detached earlobes-it’s either yes or no.

Dominant:
A form of a gene that is
expressed and masks the recessive gene. It gives the same phenotype in both
homozygous and heterozygous conditions as it expresses itself.

Ecology:
The study of the relationships
between living organisms and the natural environment.

Ecosystem:
An ecological system formed by
the interaction of living organisms (biotic) and their non-living (abiotic) environments.

Egestion:
The removal of undigested
matter from the body. Egestion would be like pooing-you’re egesting faeces
which are basically undigested food. [Different to excretion! See excretion.]

Endocrine
glands: Ductless glands that
secrete hormones into the bloodstream.

Enzymes:
Biological catalysts made of
protein. They alter the rate of (mostly catalyse) chemical reactions without themselves
being chemically changed at the end of the reactions.

Eutrophication:
The profuse growth and
multiplication of algae and green plants as a result of the enrichment of
nutrients in the water. Often leads to depletion of oxygen levels.

Excretion:
The process by which metabolic
waste products and toxic materials are removed from the body of an organism.
E.g. sweating, sweat is a metabolic waste product. [Different to egestion! See
egestion.]

Fertilisation:
The process by which the male
gamete fuses with the female gamete to form a zygote.

Focusing/accommodation:
The adjustment of the lens of
the eye so that clear images of objects at different distances are formed on
the retina.

Food
chain: A series of organisms
through which energy is transferred in the form of food.

Food
web: Two or more food chains
interlinked together.

Gamete:
A reproductive cell containing
the haploid number of chromosomes.

Gene:
A hereditary factor found on a
particular locus in a chromosome. It controls a particular characteristic and
codes for a specific protein.

Genetic
engineering: A technique used
to transfer genes from one organism to another.

Genotype:
The combination of genes in an
individual.

Gland:
A cell, tissue or an organ
that secretes chemical substances.

Habitat:
The place where an organism
lives.

Haploid:
Cells that contain half the
number of chromosomes as the parent cells which produced them.

Heterozygous:
A condition where you have
different alleles for a particular trait. E.g. if B codes for brown eyes (dominant
allele is always upper case) and the recessive allele is b (always the lower
case of the dominant alleles’ letter), then a person with a Bb genotype for eye
colour is heterozygous dominant, so will have brown eyes.

Homeostasis:
The maintenance of a constant
internal environment.

Homologous
pairs: Chromosomes which have
the same genes, shape and length.

Hormone:
A chemical substance produced
in minute quantities by an endocrine gland. It is transported in the
bloodstream to target organ(s) where it exerts its effects.

Irritability/sensitivity:
The ability of an organism to
respond to a stimulus.

Meiosis:
A form of cell division such
that the daughter cells contain half the number of chromosomes as the parent
cell. –will be haploid, e.g. to form sex cells/gametes (Chromosomes are in the
nucleus.)

Mitosis:
Cell division such that the
daughter cell produced contains the same number of chromosomes as the parent
cell. –will be diploid, e.g. to form somatic (body) cells

Mutation:
The sudden or spontaneous
change in gene structure or a chromosome, or even the chromosome number, and
may be inheritable.

Nerve:
A collection of nerve fibres.

Nerve
fibre: A long cytoplasmic
extension of the cell body of a neurone. It serves to transmit impulses.

Neurone:
A nerve cell.

Nutrition:
The intake of food and the
processes that convert food substances into living matter.

Osmoregulation:
The control of water and
solute levels in the blood to maintain a constant water potential in the body.
Basically to maintain blood water levels.

Osmosis:
The net movement of water
molecules from a solution of higher water potential to a solution of lower
water potential, through a partially permeable membrane, i.e. down a water
potential gradient. Or, from a region of
high concentration to a region of low concentration, through a partially
permeable membrane, i.e. down a concentration gradient.

Oxygen
debt: The amount of oxygen
required to oxidize the lactic acid produced in muscles during anaerobic
respiration and convert it into harmless substances.

Peristalsis:
The rhythmic wave-like
contractions of the walls of the gut.

Phagocytosis:
The process of engulfing and
ingesting foreign particles, such as bacteria, by phagocytes such as the white
blood cells.

Phenotype:
The physically expressed trait
in an individual, e.g. outward appearances such as height and eye colour.

Photosynthesis:
The process in which light
energy absorbed by chlorophyll is transformed into chemical energy.

Pollination:
The transfer of pollen grains
from an anther to a stigma.

Pollution:
The addition of substances to
the environment that damage it, making it unfit for life.

Population:
A group of organisms of the
same species living together in the same habitat.

Producers:
Organisms which convert energy
from the sun, or light energy, into chemical energy and store it as food during
photosynthesis. They are the start of the food chain.

Recessive:
A form of a gene that expresses itself only in
the homozygous condition. E.g. Bb, it won’t be expressed because the dominant ‘B’
allele masks it and is expressed instead. But in ‘bb’, this is homozygous
recessive, so it will be expressed.

I need definitions for denatured,cell respiration,concentration gradient,ileum,duodenum,home other mic, thermoregulation centre,vasodilation,mutualism,eutrophication, monoculture,eutrophication and bioaccumaulation.Please can you help me with my exam.if you don't mind can you add keywords for other science subjects too because it's really helpful for us.please,please..advance Thanks

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About Me

Hi I'm Michelle. I've finished IGCSEs and the IB but I hope these blogs help people with their IGCSEs anyway!! :)

Note: That's why these blogs are no longer updated, what's there is all I had time for back then so I'm sorry that they're not fully complete with the whole syllabus and all. Hope what's there helps anyway.. :)

I do actually have more notes than is posted, and these can be purchased by buying my IGCSE Notes sets.

Blog Archive

Hi!

Note: This blog will no longer be updated, but I will read emails.

So, I've finished IGCSEs but I'm leaving my blogs open in hopes that they help people. It would be great if you can tick a box at the bottom of each post to show me what you think, and please feel free to leave comments! A Google+1 below would be awesome too. Thank you so much, hope they help. :)

Btw, I did take information out of textbooks. But I've reworded what I can.